Iphone – How to change the UITextField so it looks like the Search Text Field

cocoa-touchiphoneiphone-sdk-3.0uitextfield

I would like to change the standard iPhone UITextField so that it looks exactly like the search text field within the UISearchBar. You can see an example of this for the SMS text entry field within the iPhone Messages application.

I do not believe that the UITextField has a style property that will meet this requirement. Any ideas?

Best Answer

If you want, you can actually extract the background image from a uisearch bar and make it a stretchable image to use as the background of a UITextField. I did the same thing and it works like a charm for me. Here's the code i used to extract it:

UIImage *img = [[[self.searchBar subviews] objectAtIndex:1] background];
NSData *imgdata = UIImagePNGRepresentation(img);

NSArray *searchPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); 
NSString *documentsDirectoryPath = [searchPaths objectAtIndex: 0];

[imgdata writeToFile:[documentsDirectoryPath stringByAppendingPathComponent:@"searchbarbg.png"] atomically:YES];

the second subview of the uisearchbar is the actual text field; this is subject to change in any future os releases though.

this will save the PNG to the app's documents directory, where you can grab it and drop it into your project and use it as the text field's background. the left and top cap widths for the stretchable image are 15 pixels.

Related Solutions

Ios – How to disable the UITableView selection

All you have to do is set the selection style on the UITableViewCell instance using either:

Objective-C:

cell.selectionStyle = UITableViewCellSelectionStyleNone;

[cell setSelectionStyle:UITableViewCellSelectionStyleNone];

Swift 2:

cell.selectionStyle = UITableViewCellSelectionStyle.None

Swift 3 and 4.x:

cell.selectionStyle = .none

Further, make sure you either don't implement -tableView:didSelectRowAtIndexPath: in your table view delegate or explicitly exclude the cells you want to have no action if you do implement it.

More info here and here

Ios – Set the maximum character length of a UITextField

While the UITextField class has no max length property, it's relatively simple to get this functionality by setting the text field's delegate and implementing the following delegate method:

Objective-C

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
    // Prevent crashing undo bug – see note below.
    if(range.length + range.location > textField.text.length)
    {
        return NO;
    }
        
    NSUInteger newLength = [textField.text length] + [string length] - range.length;
    return newLength <= 25;
}

Swift

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
    
    let currentCharacterCount = textField.text?.count ?? 0
    if range.length + range.location > currentCharacterCount {
        return false
    }
    let newLength = currentCharacterCount + string.count - range.length
    return newLength <= 25
}

Before the text field changes, the UITextField asks the delegate if the specified text should be changed. The text field has not changed at this point, so we grab it's current length and the string length we're inserting (either through pasting copied text or typing a single character using the keyboard), minus the range length. If this value is too long (more than 25 characters in this example), return NO to prohibit the change.

When typing in a single character at the end of a text field, the range.location will be the current field's length, and range.length will be 0 because we're not replacing/deleting anything. Inserting into the middle of a text field just means a different range.location, and pasting multiple characters just means string has more than one character in it.

Deleting single characters or cutting multiple characters is specified by a range with a non-zero length, and an empty string. Replacement is just a range deletion with a non-empty string.

A note on the crashing "undo" bug

As is mentioned in the comments, there is a bug with UITextField that can lead to a crash.

If you paste in to the field, but the paste is prevented by your validation implementation, the paste operation is still recorded in the application's undo buffer. If you then fire an undo (by shaking the device and confirming an Undo), the UITextField will attempt to replace the string it thinks it pasted in to itself with an empty string. This will crash because it never actually pasted the string in to itself. It will try to replace a part of the string that doesn't exist.

Fortunately you can protect the UITextField from killing itself like this. You just need to ensure that the range it proposes to replace does exist within its current string. This is what the initial sanity check above does.

swift 3.0 with copy and paste working fine.

func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {
        let str = (textView.text + text)
        if str.characters.count <= 10 {
            return true
        }
        textView.text = str.substring(to: str.index(str.startIndex, offsetBy: 10))
        return false
    }

Hope it's helpful to you.